Railway signaling apparatus



Deg-,8, 1940. V A. J. soRENsEN 2,217,528

RAILWAY SIGNALING APPARATUS Filed Aug. 8, 1939 i I i i y 6 4 I h fi 6 92 1b 0.02 Hug A TF1 y E5; 122 Egg 2-2 41 54 5.9 55 40 fiz TF 6 42 TE 55 &1; v: m

INV NTOR Andz ew a ensen.

H15 A'IZTORNEY I Patented Oct. 8, 1940 UNITED STATES PATENT OFFICE RAILWAY SIGNALING APPARATUS Application August 8, 1939, Serial No. 289,006

10 Claims.

My invention relates to railway signaling apparatus, and particularly to apparatus of this character for supplying coded current to the rails of a track section to control either wayside or cab signaling apparatus or both.

In railway signaling it has been proposed to use coded direct current of different code rates or frequencies for controlling wayside or cab signaling apparatus or both. Such impulses of direct current are preferably of high peak voltage as an aid to the shunting sensitivity of the track circuit and of short duration to require only a relatively low energy output from the current source which ordinarily is a battery. The

coding device usually provided for such systems includes a contact member which is moved into and out of engagement with a stationary contact for closing and opening the circuit connection with the current source with the result the code rate is equal to the rate such contact member is operated and high code rates place a severe operating requirement on the contact member. In other words, high code rates are difiicul-t to obtain because of the me- 5 chanical limitations of the vibrating contact member of the coding device. 7

Accordingly a feature of my invention isth provision of novel and improved means wherewith coded direct current of a predetermined 30 code rate may be obtained by use of coding means whose contact member may be operated at only a fraction of the code rate and longer life and more reliable operation of the coding means results. Other features and advantages of my 35 invention will appear as the specification progresses.

I shall describe several forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

4 In the accompanying drawing, Fig. 1 is a diagrammatic view of one form of apparatus embodying my invention when used to supply code impulses of direct current to the rails of a track section and wherewith the code rate of the our- 45 rent impulses is double the rate of operation of the coding device. Fig. 2 is a diagrammatic view of a modification of the apparatus of Fig. 1, and which also embodies my invention. Fig. 3 is a diagrammatic view of another form of 50 apparatus embodying my invention when used to supply code impulses of direct current to the rails of a track section and wherewith the code rate of the impulses may be four times the rate at which any one contact member of the coding 55 means is operated. Fig. 4 is a diagrammatic View of a modified form of the apparatus of Fig. 3 and which also embodies of my invention.

In each of the several views like reference characters designate similar parts.

Referring to Fig. 1, the reference characters la and lb designate the track rails of a stretch of railway track which is formed'with a track section AB by the usual insulated rail joints, and which track section may be one section of a series of consecutive sections of a wayside and/or 10 cab signal system.

The track sec-tion AB is provided with a track circuit which includes means for supplying to the rails at the exit end of the section code impulses of direct current, and a track re- 15 lay responsive to such code impulses of current connected across the rails at the entrance end of the section. Such track relay is not shown in the drawing of the present application since such track relays are well known in the art 2 and they form no part of my present invention. In case of cab signals the train is equipped with an inductor mounted on the train in advance of the leading pair of wheels and in inductive relation with the track rails in the wellknown manner.

The means for supplying such code impulses of direct current consists of a reactance device or transformer TF, a battery 5 and a coding device indicated as a whole by the reference character'CD. As here shown the secondary winding 6 of transformer TB is connected across the track rails la and lb over wires I and 8',-respectively. The primary winding 9 of transformer TF has one terminal connected with one terminal of battery 5 over wire l0 and has its otherterminal connected with the other terminal of battery 5 over a contact member of coding device CD as will shortly be explained.

The coding device CD comprises a polar re-' lay PR, a transformer TI and a condenser H. The secondary winding I2 of transformer TI is connected in series with condenser ll across the operating winding 28 of relay PR. Windings l2 and 28 and condenser II are proportioned to provide a resonant circuit and for the purpose of illustration I shall assume this circuit has a natural period of 180 cycles per minute or 3 cycles per second. The primary winding l3 of transformer Ti has its two outside terminals connec-ted with normal polar contact l4 and reverse polar contact l5 of relay PR over wires l6 and I1, respectively. The center terminal of primary winding I3 is connected with one terminal of a battery l8 over wire l9, and the other terminal of battery i8 is connected with a contact member 2! of relay PR over wire 20, contact member 2! being adaptable of engaging either normal contact M or reverse contact i5.

Polar relay PR is provided with a second contact member 22 adaptable of engaging either a normal polar contact 2-3 or a reverse polar contact 26. Normal contact 23 and reverse contact 2d are connected together by wire 25 and the two contacts in multiple are connected with the other terminal of primary winding 9 of transformer TF over wire 26, contact member 22 being connected with the other terminal of battery 5 over wire 2'8 to complete a circuit by which direct current is supplied from battery 5 to primary Winding 9. When current of one polarity which I shall term normal polarity is supplied to the operating winding 28 of polar relay PR its contact members 2| and 22 are operated to their left-hand position, that is, the position illustrated by solid lines in Fig. 1, where they engage normal polar contacts M and 23, respectively. When current of reverse polarity is supplied to winding 2% of relay PR the contact members 2i and 32 are operated to their right-hand positions, that is, the positions illustrated by dash lines, where they engage reverse polar contacts l5 and 2 3, respectively.

In explaining the operation of the apparatus of Fig. l, I shall assume that relay PR has just been operated to its reverse position closing contact 2ll5 so that current flows in the lower portion of primary winding l3 of transformer T1. During the building up of the current to its steady value, an electromotive force is induced in secondary winding l2 of transformer Tl of a selected polarity and which electromotive force excites the resonant circuit so that the current flowing therein oscillates at the natural period of the circuit. The parts are so arranged that during the first charge of condenser l i, the current flowing in the resonant circuit is of the direction that energizes relay PR at reverse polarity so that contact members 2! and 22 of relay PR are held at the reverse or right-hand position.

When condenser ll next discharges due to the free oscillations set up in the resonant circuit, the current flows in the circuit in the opposite direction to that flowing in the circuit when condenser H was charged so that relay PR now becomes energized at normal polarity and its contact members 2! and 22 are operated to their normal or left-hand positions. Upon opening contact 2ll5, the current decays in the lower portion of primary winding !3 and upon closing contact 2 ll i current builds up to a steady value in the top portion of primary winding 13. The connections are such that this dying down and building up of current in the two portions of primary winding l3 unite to induce an electromotive force in secondary winding [2 which causes current to flow in the resonant circuit that energizes relay PR at normal polarity and again charges condenser H. Since this charging current is of the same polarity as that which operated relay PR to close its normal contacts, the contact members 2| and 22 are held at the normal position. When condenser ll next discharges, however, the relay PR is energized at reverse polarity and its contact members are operated back to their reverse or right-hand positions. The current flowing in the top portion of primary winding I3 now decays and the current flowing in the lower portion of primary winding 13 builds up to a steady value and it follows that an electromotice force is now induced in secondary winding l2 which causes current to flow in the resonant circuit that energizes relay PR at reverse polarity and charges condenser H. This cycle of operation just described is then repeated over and over again, the relay PR being operated at a rate which corresponds to the natural period at which the resonant circuit is proportioned and which period I have here assumed for the purpose of illustration to be cycles per minute.

It is clear that either the inductance or the capacity or both of the resonant circuit including winding 28 of relay PR can be readily varied according to different traffic conditions so that relay PR is operated at a different predetermined rate for each different traffic condition.

The contact member 22 is operated to alternately engage normal contact 23 and reverse contact 26 at the rate at which relay PR is operated, the period the contact member 22 engages contact 23 or contact 2d being approximately one-half of each operation cycle of the relay, and the period contact member 22 is in transit and not in engagement with either contact 23 or 24 being relatively short and only a small portion of the operation cycle.

Each period contact 2223 or 22-2d is closed current builds up in the primary winding 9 of transformer TF, the current building up to approximately the steady value because of the relatively long period contact 22-23 or 22-44 is closed. When contact member 22 is in transit between its two extreme positions the circuit for primary winding 9 is opened and the energy stored in the magnetic circuit of transformer TF decays. The parts are so proportioned as to the time constant of the circuit including primary winding 9 that the energy builds up relatively slowly in transformer T5 and the electromotive force induced in secondary winding 6 thereby is small and can be neglected. The decay of the stored energy is relatively rapid and a relatively large electrornotive force is induced in secondary winding 5 and in turn applied across the track rails causing a current impulse to flow in the rails. It follows that two efiective code impulses of current are supplied to the rails of track section AB each operation cycle of the coding device CD, each movement of contact member 22 being eifective to produce current impulse.

Since current flows in primary winding 9 always in the same direction and the effective electromotive force induced in secondary winding 6 is caused by the decay of the stored energy, the effective current impulses supplied to the rails of section AB are all of like polarity.

In Fig. 2, the track rails la and ii; are formed with a track section A--B, across the rails at the exit end of which is connected secondary winding 6 of track transformer TP the same as in Fig. 1. .The primary winding 9 of transformer TB of Fig. 2 is connected with battery over a contact member 39 of a coding device CDl, acondenser 29 being preferably connected across the terminals of primary winding 9.

- The coding device CD! comprises a polar relay PRI having a normal winding NW and a reverse winding RW and is provided with a contact membe! 36 capable of making engagement with either a normal polar contact 3! or a reverse polar contact 32. Polar relay PR! is preferably characterized bythe fact that the stroke of its polar armature to which contact member 39 is attached will be completed if energy is applied to either winding for along enough interval to open the polar contact in the last position. In other words, when current is supplied to winding NW or RW for an interval long enough to move contact member 30 away from its last position the contact member 3'0 is moved to its other extreme position without further energization of the respective winding. A relay which may be made to operate in the manner just described is covered by Letters Patent of the United States, No. 1,790,671 granted to Branko Lazich on February 3, 1931, for Electrical relays. In the instant application the polar relay PRI is provided with two windings disposed for reversibly energizing the relay whereas in the patent the relay is shown provided with a single winding to which current is reversibly supplied, such equivalent arrangements for the windings of a polar relay being readily understood by those skilled in the art.

Assuming relay PRI to be at its normal position, that is, the position shown in Fig. 2, current flows from one terminal of battery 5 over reverse winding RW, normal polar contact 39-3 I, winding 9 of transformer TF and to the other terminal of battery 5. This current gradually increases until it reaches a value sufiiciently high to operate the relay, at which point the contact member 30 is moved to break engagement with normal contact 3I and to make engagement with reverse contact 32, it being understood, of course, that winding RW is so connected as to energize relay PRI at reverse polarity. While current is building up magnetic energy is stored in transformer TF. The parts of the circuit including primary winding 9 are preferably so'designed with respect to the time constant of the circuit that energy builds up rather slowly and the voltage induced in secondary winding 6 at this time is so small that it can be neglected. While contact member 30 is in transit the circuit is interrupted and the stored magnetic energy in transformer TF decays and. by transformer action a relatively high electromotive force is induced in secondary winding 6 which in turn causes an impulse of current to flow in the track rails of section AB, the condenser 29 aiding in the operation. When contact member 39 engages contact 32 current flows from battery 5 over normal winding NW, reverse polar contact 30-32, primary winding 9 and back to battery 5.

Again current gradually increases until it reaches a value sufiiciently high to operate relay PRI at which point contact member 30 is moved back to its normal position, since winding NW is connected to energize the relay at normal polarity. While the current is building up magnetic energy is again stored in transformer TF but because of the time constant of the circuit little or no voltage is induced in secondary winding 6. However, when contact member 30 is in transit back to its normal position the circuit is interrupted and a relatively high electromotive force is induced in secondary winding 6 and an efiective current impulse is supplied to the track rails because of the rapid decay of the energy stored in transformer TF. The windingsof relay PRI and of transformer TF are so adjusted and proportioned that when current is sufficiently strong to operate the relay a value of the current has been reached that causes a current impulse of proper magnitude to be supplied to the track rails. The parts are further so proportioned that relay lPRI is operated at a predeterperiods of the relays.

mined rate of say, for example, 180 cycles per minute or 3 cycles per second.

It is to be observed that two current impulses are supplied to the track rails each operation of the coding device CDI of Fig. 2. That is to say the contact member 30 of relay PRI is effective during each movementto cause an effective current impulse to be supplied to the track rails. Since the current supplied from battery 5 to primary winding 9 always flows in the same direction in winding 9 and since the eifective current impulse supplied to the track rails is always produced by the decay of the stored energy the current impulses flowing in the rails are all of the same polarity.

In Fig. 3, the secondary winding 6 of track transformer TF is connected across the rails la and lb at the exit end of track section AB the same as in Fig. 1. The primary winding 9 of transformer TF of Fig. 3 is supplied from battery 5 with current which is periodically interrupted or coded by a'coding device CD2. Coding device CD2 comprises two slow acting relays RI and R2 both of which are operated by current supplied from battery 5. Relay RI controls over its front contact 33 the energization of relay R2, and relay R2 controls over its back contact 34 the energization of relay RI as will be readily understood by an inspection of Fig. 3. Consequently, as long as current is supplied by battery 5, relays RI and R2 are operated in a cyclic manner, the rate of operation being determined by the retardation In other Words, coding device CD2 divides time into successive operation cycles or periods each of which is subdivided into four substantially equal intervals. To be explicit, and assuming at the start that both relays RI and R2 are released, current first flows from the left-hand terminal of battery 5 over winding of relay RI, back contact 34 of relay R2 and to the right-hand terminal of battery 5, and relay RI is picked up at the end of its slow pick-up period to close front contact 33 which completes the first interval of the operation period or cycle. With front contact 33 closed current flows from battery 5 over front contact 33, winding of relay R2 and back to battery and relay R2 is picked up at the end of its slowpick-up period to open back contact 34 completing the second interval of the operation period. With back contact 34 opened relay RI is deenergized and releases, at the end of its slow release period to open front contact 33 completing the third interval of the operation period. With front contact 33 opened relay R2 is deenergized and releases at the end of its slow release period to close back contact 34 and thereby completesthe fourth interval of the operation period. Both relays RI and R2 are now released ready to start a second operation cycle. Obviously the above described operation cycle will be completed over and over again as long as current is supplied from battery 5 to relays RI and R2.

Relays RI and R2 are provided with contact members 39 and 40, respectively, for controlling the supply of current from battery 5 to primary winding 3 of transformer TF. Contact member 39 of relay RI is connected with one terminal of primary winding'9 while" front contact 35 and back contact 36 associated with contact member 39 are connected in multiple and the two are connected in series with contact member 40 of relay R2. Front contact 38 and back contact 31 associated with contact member 40 are connected in multipleand thetwo areconnected with one terminal of battery 5, the other terminal of battery being connected with the other ter-- minal of primary winding 9 to complete the circuit therefor.

It is clear that during the first interval of an operation cycle of coding device CD2, current is supplied from battery 5 to primary winding 9 over a circuit including contact 3936 of relay RI in series with contact 493I of relay R2, and energy is stored in transformer TF, the time constant of the circuit being such however that little or no voltage is induced in secondary Winding i3 during the building up of the current. At the end of the first interval of the operation cycle of coding device CD2 relay RI is picked up to move contact member 39 from engagement with back contact 3.5 to engagement with front contact 35, the circuit for primary winding 9 is interrupted while contact member 39 is in transit and an electromotive force is induced in secondary winding 6 due to the decay of the stored energy in transformer TF, and which electromotive force causes a first current impulse to be supplied to the rails of section AB. During the second interval of the operation cycle current again is supplied to primary winding 9 over a circuit including contact 39-95 of relay RI in series with contact iii3'l of relay R2, and energy is again stored in transformer TF. At the end of the second interval, relay R2 is picked up, the circuit for primary'winding 9 is interrupted while contact member 49 is in transit between back contact 37 and front contact 38 and an electromotive force is induced in secondary winding 6 due to the decay of the stored energy so that a second current impulse is supplied to the track rails. During the third interval of the operation cycle energy is stored in transformer TF due to current supplied from battery 5 to pri mary winding 9 over a circuit including contact 3935 of relay RI in series with contact 4038 of relay R2. At the end of the third interval relay RI is released and the circuit is interrupted while contact member 39 is in transit between front contact 35 and back contact 35 and a third current impulse is supplied to the track rails due to the decay of the energy stored in transformer TF. During the fourth interval of the operation cycle current flows to primary winding 9 from battery 5 over contact 39-36 of relay RI in series with contact 49-38 of relay R2 and energy is again stored in transformer TF so that at the end of the fourth interval relay R2 is released interrupting the circuit so that while contact member 41; is in transit between front contact 38 and back contact 31 a fourth current impulse is supplied to the track rails.

Consequently four current impulses are supplied to the rails of section A-B each operation cycle of coding device CD2 and a relatively high code rate of current impulses can be obtained with relatively low operation rate for the coding device.

In the form of the invention disclosed in Fig. 4, the secondary winding 6 of track transformer TF is connected in series with a secondary winding H of a second track transformer TFI across the rails la and lb at the exit end of section A-B. In Fig. 4, the coding device CD2 comprises two slow acting relays RI and R2 the same as in Fig. 3 with the result that each operation cycle of the coding device is divided into four substantially equal intervals.

Assuming both relays RI and R2 of Fig. 4 are released, current is supplied from battery 5 to primary Winding 9 of transformer TF over contact 39-39 of relay RI and current is supplied to primary Winding 42 of transformer TFI over contact W-3'I of relay R2, and magnetic energy is stored in both transformers TF and TFI. At the end of the first interval of the operation cycle relay RI is picked up to transfer contact member 39 from engagement with back contact 2-35 into engagement with front contact 35, the circuit for primary Winding 9 of transformer TF is interrupted and an electromotive force is induced in secondary winding 6 which causes a first current impulse to be supplied to the track rails. With contact 3935 of relay RI closed current again is supplied to the primary winding 9 and energy is again stored in transformer TF. At the end of the second interval of the operation cycle relay R2 is picked up to transfer contact member 4' 8 from engagement with back contact 3'! into engagement with front contact 38, the circuit for primary winding 42 of transformer TFI is interrupted and an electromotive force is induced in secondary winding M of transformer 'IFi which electromotive force causes a second current impulse to be supplied to the track rails. At the end of the third interval of the operation cycle relay R! is released and the circuit for primary winding 9 is interrupted while contact member 39 is in transit between front contact 35 and back contact 36. Under these conditions, a third impulse of current is supplied to the traelcrails due to the decay of the energy stored in transformer TF. At the end of the fourth interval rela R2 is released and the cir- N cult for primary winding 32 of transformer TFI is interrupted while contact member 49 is in transit between front contact 38 and back contact 32 so that a fourth impulse of current is supplied to the rails due to the electromotive force induced in secondary winding II of transformer TFI because of the decay of the magnetic energy stored therein.

It clear therefore that the apparatus of Fig. i is effective to cause four current impulses to be supplied to the track rails of section A-B during each operation cycle of the associated coding device CD2, and that the impulses are transmitted alternately from transformers TF and TFI.

Although I have herein shown and described only a few forms of apparatus embodying my invention, it is understood that Various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

i. In combination, a section of railway track, a track transformer having a secondary winding connected across the rails of said section, a source of direct current, a coding device having a contact member operable to a first and a second position for engaging a first and a second contact respectively, means for operating said device, and circuit means including said contact member in series with said first and second contacts in multiple to connect said source of direct current across the primary winding of said transformer to supply to the rails of said section an effective code impulse of direct current each time said contact member is in transit between said first and second contacts.

2. In combination, a section of railway track, a track transformer having a secondary winding a normal and a reverse polar contact of said connected across the rails of said section, a source of direct current, a normally active coding device having a contact member periodically moved between a first and a second position for periodically engagin a first and a second contact respectively, and circuit means including said contact member in series with said first and second contacts in multiple to connect said current source with a primary winding of said transformer to supply to the rails of said section an effective code impulse of current each time said contact member is moved between its two positions.

3. In combination, a section of railway track, a source of direct current, a coding device having a contact member operable to a first and a second position to engage a first and a second contact respectively, means to operate said cod ing device at a predetermined rate, and circuit means including said contact member in series with said first and second contacts in multiple to connect said current source with the rails of said section for supplying to the rails effective code impulses of direct current at a rate equal to twice said predetermined rate.

4. In combination, a section of railway track, a track transformer having a secondary winding connected across the rails of said section, a source of direct current, a polar relay having a first and a second contact member each of which is adaptable of engaging a normal and a reverse polar contact, means including a current source and said first contact member with its associated normal and reverse polar contacts to reversibly energize said relay to cause the relay to be operated at a predetermined rate, and circuit means including said second contact member and its normal and reverse polar contacts connected in multiple to connect said source of direct current across a primary winding of said transformer to supply to the rails of said section effective code impulses of direct current at a rate equal to twice said predetermined rate.

5. In combination, a section of railway track, a track transformer having a secondary winding connected across the rails of said section, a source of direct current, a polar relay having a first and a second contact member each capable of engaging respective normal and reverse polar contacts, another transformer having a secondary winding connected with the winding of said relay, another source of direct current, means including said first contact member with its associated normal and reverse contacts to alternately connect said other source to a first and a second portion of the primary winding of said other transformer to cause said relay to be reversibly energized by the electromotive forces induced in said secondary winding to operate the relay at a predetermined rate, and means including said second contact member with its associated normal and reverse contacts connected in multiple to connect said first mentioned current source with a primary winding of said track transformer to supply to the rails of said section effective code impulses of direct current at a rate equal to twice said predetermined rate.

6. In combination, a section of railway track, a track transformer having a secondary winding connected across the rails of said section, a source of direct current, a polar relay, another transformer having a secondary winding connected with a winding of said relay through a condenser to form a resonant circuit tuned to resonance at a predetermined frequency, means including relay to alternately supply direct current to two portions of a primary winding of said other transformer to excite said resonant circuit by the electromotive forces induced in said secondary winding to operate said relay at a rate equal to said predetermined frequency, and means including another polar contact of said relay to connect said source of direct current with a primary winding of said track transformer to supply code impulses of direct current to the rails of said section at a rate determined by the rate at which said relay is operated.

'7. In combination, a section'of railway track, a track transformer having a secondary winding connected across the rails of said section, a source of direct current having one terminal connected with one terminal of a primary winding of said transformer, a polar relay having a normal winding and a reverse winding, a first circuit means including said normal winding and a reverse polar contact of said relay to connect the other terminal of said current source with the other terminal of said primary Winding, and a second circuit means including said reverse winding and a normal polar contact of said relay to connectsaid other terminal of said source with said other terminal of said primary winding whereby said relay is operated at a predetermined rate and effective code impulses of a rate equal to twice said predetermined rate are supplied to the rails of said section.

8. In combination, a section of railway track, a track transformer having a secondary winding connected across the rails of said section, a source of direct current having one terminal connected with one terminal of a primary winding of said transformer, a polar relay having a normal winding and a reverse winding, and circuit means to connect the other terminal of said current source with the other terminal of said primary winding either over said normal winding and a reverse polar contact of the relay or over said reverse winding and a normal polar contact of the relay, and said circuit means proportioned to cause said relay to be operated at a predetermined rate so that effective code impulses of direct current of a rate equal to twice said predetermined rate are supplied to the rails of said section.

9. In combination, a section of railway track, a first and a second track transformer having secondary windings connected in series across the rails .of said section, a source of direct current,

a first and a second relay arranged with said vals, means including a front and a back contact of said first relay in multiple to connect said current source with the primary winding of said first transformer to supply an effective impulse of current to the rails of said section duringfthe first and the third interval of each said cycle, and means including a front and a back contact of said second relay in multiple to connect said current source with the primary winding of said second transformer to supply an effective impulse of current to the rails of said section during the second and the fourth intervals of each said cycle.

10. In combination, a section of railway track,

a first and a second transformer the secondary windings of which are connected in series across the rails of said section, a source of direct current, coding means having a predetermined operation cycle which is subdivided into four substantially equal intervals, and circuit means including a first and a secondvcontact of said coding means in multiple to connect said current source with the primary Winding of said first transformer and including a third and a fourth contact of said coding means in multiple to connect said current source with the primary winding of said second transformer, and said first and second contacts opened during the first and third intervals respectively of each cycle and said third and .fourth contacts opened during the second and fourth intervals respectively of each cycle to supply to the rails of said section four effective impulses of current each cycle of said coding means,

ANDREW J. SORENSEN. 

